Flying High on Hydrogen

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

AeroVironment announced that their Global Observer™ reached an altitude of 5,000 feet (mean sea level) over Edwards Air Force Base and stayed up for four hours – all on its hydrogen-powered electric motors.  Having made its first flights last August and September on battery power, the Global Observer on January 11, 2011 successfully demonstrated the system that will allow it to stay airborne for up to a week at a time, staying on station at 65,000 feet. This ability to maintain “persistent” communications and surveillance enables to the Global Observer to be flown in from areas remote from a combat theater or natural disaster location, and to uninterrupted observation of the situation.  AeroVironment claims that, “Two Global Observer aircraft, each flying for up to a week at a time, will alternate coverage over any area on the earth, providing a seamless, persistent platform for high value missions such as communications relay, remote sensing, long-term surveillance and border patrol. Offering greater …

Another Cure for Range Anxiety

Dean Sigler Electric Powerplants, Sustainable Aviation 2 Comments

Or at least an approach to provide angst-free cross-country flying, as Michael Friend explained in his Electric Aircraft Symposium presentation last April at Rohnert Park, California.  Friend, a Boeing engineer closely tied to the company’s early fuel cell work, is the owner and pilot of N787M, one of the earliest production kit Silence Twisters.  The Twister is a Spitfire-like, retractable-gear light aircraft capable of cruising 146 on its Jabiru 80-horsepower engine.  It’s capable of full aerobatic flight, and was converted to electric power in Germany for possible airshow demonstrations.  The Twister’s designers also plan a lengthened wing that would make motor gliding possible. Friend noted the difference in energy density between available batteries and gasoline, explaining that 10 kilograms of gasoline (22 pounds – or about 3.75 gallons) had the energy of 450 kilograms (990 pounds) of lithium batteries.  The gasoline cost $10 (April prices) while the battery pack cost $36,000.  Despite the fact that the batteries will run through …

The Happiest Materials Scientist

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

According to his NASA biography, “Dr. Ajay Misra, a member of the Senior Executive Service, is Chief of the Structures and Materials Division in the Research & Technology Directorate at the NASA Glenn Research Center in Cleveland, Ohio.  In this position, Dr. Misra has the responsibility for planning, advocating, coordinating, organizing, directing and supervising all phases of Division research and business activities.”  At the fourth annual Electric Aircraft Symposium in Rohnert Park, California in April 2010, Dr. Misra was among the most charming and happiest of presenters – probably because he had so many happy things to talk about.  Much of the joy comes from the continuing revelations about the characteristics of carbon and boron nanotubes.  They turn out to be absolutely wonderful for thermal, structural, battery, capacitor and motor applications.  Dr. Misra’s talk sounded at times like a pitch for a wonder cure-all, but one backed with solid scientific precepts. Boron nitrate nanotubes have better high-temperature characteristics than carbon …

First Rollout of a Green Flight Challenge Flyer

Dean Sigler Electric Powerplants, GFC Leave a Comment

On November 22, 2010, PC-Aero rolled out Elektra One with a running motor, the Geiger HP-13.5 unit normally found on paramotors, trikes, and the Swift flown by Manfred Ruhmer.  Testing and the public unveiling took place at the Rotortec Company in Gonsried, Germany.  The airplane had shed the tricycle gear  it displayed at the Friedrichshafen Expo for Sustainable Mobility, where it had been a centerpiece in June, 2010.  It now sports what looks like a center-line retractable gear much like that of the Fournier motor gliders. A month later, December 22, the team “performed successfully the static tests of Elektra One for the German Ultralight Certification. The structure of the aircraft (wing, fuselage and tails) [were] loaded up to limit load.”  Test flights are set for January, and the aircraft is scheduled to participate in the Green Flight Challenge in July at Santa Rosa, California.  There, it will have to fly a  200 mile closed course on a single charge of its batteries at …

Batteries Not Included

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 The University of New South Wales has a long-term solar development program that produces some of the most competitive solar racers in the world – evidenced by their taking a world speed record for solar-only vehicles on January 7 at Nowra, Australia.  Their record run was witnessed and awarded on the spot by Guinness World Record officials. “Designed and built by UNSW students, Sunswift IVy is a three-wheeled vehicle with a monocoque carbon fiber body, brushless CSIRO 3 phase DC 1800 W motor, solar array producing about 1200 W (the same it takes to run a toaster) and, usually, a 24.75 kg (55.56 lb) lithium ion polymer battery pack. However, as the milestone is for cars powered exclusively by silicon solar cells, the battery was removed for the record attempt.” Normally driven by engineering students, the car was handled this day by two professional race drivers.  Despite partially-clouded skies which ended in rain, the team managed a speed of 88.8 …

Thin, Light, Strong, and Energy Dense

Dean Sigler Electric Powerplants, Sustainable Aviation 2 Comments

 2010’s Nobel Prize in Physics went to Andre Geim and Konstantin Novoselov, who extracted graphene from a piece of graphite when they stuck a piece of adhesive tape to it and peeled away a single atom-thick layer of the thinnest, strongest material in the world. The Nobel Prize web site explains other remarkable properties of this new material.  “As a conductor of electricity it performs as well as copper. As a conductor of heat it outperforms all other known materials. It is almost completely transparent, yet so dense that not even helium, the smallest gas atom, can pass through it. Carbon, the basis of all known life on earth, has surprised us once again.” With studies in quantum physics and materials science possible, practical applications loom.  “Also a vast variety of practical applications now appear possible including the creation of new materials and the manufacture of innovative electronics.  Graphene transistors are predicted to be substantially faster than today’s silicon transistors …

CAFE News: Comparing Apples, Bananas, Oranges and Doughnuts

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

One of the problems facing judges in the July Green Flight Challenge the CAFE Foundation is managing for NASA is that of determining fairly who gets the best fuel mileage.  Since “fuel” in this case can be traditional aviation gasoline, bio-diesel, electricity from batteries or solar panels, or some other energy storage medium, wildly different energy densities have to be taken into account. If TSA “freedom feels” seem intrusive, the scrutiny applied to GFC entrants and their craft will be even more onerous.  Aircraft will be impounded once inspected and registered, and the only contact pilots may have with their planes before taking off will be to “top off” their fuel tanks or batteries just before the start of their flight – all under constant monitoring. The widely and wildly differing energy densities for the different forms of motive power require careful definition of energy equivalencies.  One pound of gasoline, for instance, equals about 20,000 BTU, or 5.8 kilowatt hours, …

A Record Book for the Filling

Dean Sigler Electric Powerplants, Sustainable Aviation 2 Comments

The Federation Aeronautique Internationale (FAI), standards setter and record keeper for the aviation world, recently added new classes of records, including those for solar-powered airplanes (CS).  Such classes can be broken down by sub-class and category as necessary. Qinetiq’s Zephyr unmanned aerial vehicle (UAV) achieved several records in the UAV category in July, and these were made official December 23 by the FAI – a neat Christmas gift to the team.  As noted in Qinetiq’s press release: “The FAI has ratified three records which the QinetiQ HALE Team claimed following Zephyr’s long duration flight in July 2010: • Absolute duration record Unmanned – The longest flying UAV in the world (beating Global Hawk’s record by a factor of 11) at 336 hours 22 minutes 8 seconds • Class Record UAV (50-500kg) – Altitude: At a height of 21,562m (which is also 5,000ft higher than Global Hawk, albeit in a different category). • Class Record UAV (50-500kg) – Duration: As above.” In the …

Sunseeker III Becomes the Duo

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Dropping a digit and its Latinate numeration, the recently renamed Sunseeker, a joint collaboration between Eric Raymond and a group of German, Swiss, Polish and Slovenian contributors, is showing progress towards its 2011 test flights. The 23-meter (75.46 feet) span solar-powered sailplane takes its wing from the Stuttgart Akaflieg Icare II, its fuselage from the Stemme basic profiles, is being built at least partially in Poland, and uses an electric motor designed by Slovenian native Roman Susnik, as noted in an earlier entry. The craft’s specifications provide evidence of the care employed in the design and construction of this lightweight marvel.  A 75-foot wing aircraft weighing 270 kilograms (594 pounds) empty and 470 kilograms ( 1,034 pounds) when carrying two in its side-by-side cockpit is an achievement.  Compare that to the 345 kg (765 pounds) empty weight and 550 kg (1,220 pounds) maximum weight of a “light” Piper Cub, with only a 36-foot, strut-braced wing.    The 13.8 pounds-per-foot span loading (compare to the Cub’s 33.9 pounds-per …

Tripling Battery Range and Quelling Anxieties – Or Adding to Them?

Dean Sigler Electric Powerplants 1 Comment

Having recently been allowed a test drive in a Nissan Leaf , in which the late autumn leaves falling on the car made more noise than the car, I was taken by the quiet, the reasonable performance, and general sense of how much more refined everything is than on my well-worn 1995 internal-combustion vehicle.  Cars are indeed getting better, but an issue remains with electric cars and airplanes – range.  The Nissan representatives, a lively bunch of presenters who took prospective drivers through a “pre-flight” education program, admitted that shortcoming, and promised a coming series of charging stations dotting the I-5 from Canada to Mexico at 100-mile intervals, the demonstrated range for the Leaf. Israeli entrepreneur Shai Agassi has come up with an interesting twist on recharging, distributing battery switching stations around Israel.  A customer pulls into the station and drives the nearly discharged vehicle over a pit, in which a robotized conveyor system and associated machines disconnect the drained battery and …